The invention relates generally to intra-oral light therapy apparatuses and methods for using the same, including methods for regulating and/or facilitating orthodontic tooth movement.
Orthodontics involves the movement of teeth through bone. By applying pressure to a tooth, bone can be broken down at a leading edge of the tooth to facilitate tooth movement. New bone is then created at a trailing edge of the tooth. Bone is resorbed in (e.g., broken down) in areas of pressure between a tooth root and periodontium, and bone is deposited (created) in areas of tension between a tooth root and periodontium. Pressure can cause resorption and tension can cause deposition regardless of where they occur along a tooth root surface. Movement of teeth through bone is slow based on the speed of the remodeling process while teeth are undergoing conventional orthodontic treatment, thereby necessitating treatments of long duration in order to achieve the desired tooth position. Tooth movement in adults is slower than tooth movement in adolescents. Long-term orthodontic treatment can have an increased risk of root resorption, gingival inflammation and dental caries. Moreover, movement of teeth through bone can be uneven, as teeth might “tip” due to the force applied, i.e., the crown of the tooth can move in the desired direction more quickly than the root of the tooth, resulting in tipped movement of the tooth. When teeth move “bodily” through the bone, i.e., in a more or less perpendicular orientation relative to the bone, the teeth move without tipped movement or with only a low degree of tipped movement.
Methods for increasing the rate of tooth movement without damage to the tooth and periodontium have been sought. For example, acceleration of tooth movement can be achieved by the local injection of prostaglandin, the active form of vitamin D3, and osteocalcin around the alveolar socket. These substances might increase the rate of tooth movement, but might also cause side effects such as local pain and discomfort for a patient during the process of injection. An alternative strategy for increasing the rate of tooth movement is to improve bone regeneration. For example, light therapy has been found to be effective in the treatment of bone disorders and the biostimulation of bone and soft tissue, and can be effective in accelerating alveolar bone regeneration. Light can stimulate a variety of biological activities in cells and tissues that are compromised in function, for example, by stimulating cytochrome C oxidase or nitric oxide synthase.
Known phototherapy or light therapy treatments are typically administered by a dentist, orthodontist, physician or therapist who directs light from a hand-held light emitting apparatus at an affected area. Known light emitting apparatuses can be difficult to position consistently over the affected area. Thus, known methods for light therapy are often administered by a practitioner in a clinical setting. This also allows for the practitioner to manually address compliance and safety concerns. For example, by performing the light therapy in a clinical setting, the practitioner can supervise a patient's compliance with a prescribed light therapy treatment program. Even with such manual supervision, however, the likelihood still exists that a patient may skip a scheduled or prescribed treatment session or fail to maintain a log documenting the therapeutic sessions. Thus, the practitioner prescribing the treatment program may be unable to accurately assess whether the patient is benefiting from use of the light emitting apparatus.
Additionally, the use of known devices for light therapy can present other complications and/or risks associated with emitting light when not being directed to the affected area. For example, light directed to a different part of the patient's anatomy (e.g., the eyes) potentially may be harmful. Moreover, the temperature of a light emitting apparatus may exceed a desired temperature threshold, thus subjecting the patient to potential harm. More particularly, various regulations and/or industry standards have been promulgated to address safety concerns, including concerns related to excessive temperature, for light emitting apparatuses. For example, the International Electrotechnical Commission (“IEC”) has promulgated Standards No. 60601, which sets forth general basic safety and performance requirements for medical electrical equipment. More specifically, IEC Standards No. 60601-2-57 sets forth safety and performance requirements for light source equipment intended for therapeutic and other uses, and IEC Standards No. 60601-1-11 sets forth requirements for medical electrical equipment and systems used in the home environment. In another example, the IEC has promulgated Standards No. 62471, which addresses the photobiological safety of lamps and lamp systems. The compliance with these, and any other applicable standards, can present challenges for known methods and systems for light therapy.
Additionally, intra-oral light therapy typically involves repeated treatments over at least several days. Accordingly, known methods for intra-oral light therapy involves patients undergoing the light therapy to make multiple visits to a practitioner's office or clinic in order to complete a therapy regimen. Such repeated visits can be time consuming or expensive
Furthermore, in a recent study, more than 65% of the subjects in North America were shown to be deficient vitamin D serum levels. In these vitamin D-deficient subjects, bone metabolism and remodeling can be adversely affected.
Thus, a need exists for methods and apparatuses that are useful for increasing the velocity (or rate) or improving the quality of tooth movement through bone in response to orthodontic treatment, to decrease treatment times for patients without undesirable side effects or pain. There is also a need for methods and apparatuses that can be used to achieve a desired mode or quality of movement of teeth through the bone, e.g., bodily movement of teeth through bone, using intra-orally administered light therapy that permits tooth movement to be modulated at a desired specific location or locations within a patient's mouth without undue difficulty. A need also exits for methods and apparatuses that can be used to administer light therapy in a home environment that monitor patient compliance with a prescribed treatment program. A need further exists for methods and apparatuses configured to address patient safety concerns associated with self-administration of light therapy in a home environment, including ensuring compliance of the apparatuses with applicable safety and performance regulations and/or standards.
Additionally, some known orthodontic treatment regimens include wearing each of a set of orthodontic appliances, such as custom-made aligners, in a predetermined sequence, each for a period of time. Known methods for treatment using such aligners often specify a fixed time period during (e.g., six days) during which each aligner should be worn. Known methods do not provide a method for employing a time period that is associated with the specific patient (i.e., that takes into account the patient's specific rate of tooth movement). Moreover, known methods for treatment using aligners do not include light therapy. Thus, a need exists for improved methods and apparatus for determining a period of time during which an orthodontic appliance should be worn.